code: def setUp(self):
      super(SpecgramsHelperTest, self).setUp()
      self.data_filename = os.path.join(
          tf.resource_loader.get_data_files_path(),
          "../../../testdata/example_nsynth_audio.npy",
      )
      audio = np.load(self.data_filename)
      # Reduce batch size and audio length to speed up test
      self.batch_size = 2
      self.sr = 16000
      self.audio_length = int(self.sr * 0.5)
      self.audio_np = audio[
          : self.batch_size, : self.audio_length, np.newaxis
      ]
      self.audio = tf.convert_to_tensor(self.audio_np)
      # Test the standard configuration of SpecgramsHelper
      self.spec_shape = [128, 1024]
      self.overlap = 0.75
      self.sh = specgrams_helper.SpecgramsHelper(
          audio_length=self.audio_length,
          spec_shape=tuple(self.spec_shape),
          overlap=self.overlap,
          sample_rate=self.sr,
          mel_downscale=1,
          ifreq=True,
          discard_dc=True,
      )
      self.transform_pairs = {
          "stfts": (self.sh.waves_to_stfts, self.sh.stfts_to_waves),
          "specgrams": (
              self.sh.waves_to_specgrams,
              self.sh.specgrams_to_waves,
          ),
          "melspecgrams": (
              self.sh.waves_to_melspecgrams,
              self.sh.melspecgrams_to_waves,
          ),
      }
  
file_path: magenta/magenta/models/gansynth/lib/specgrams_helper_test.py
imports: import os
  from absl import flags
  from absl.testing import parameterized
  from magenta.models.gansynth.lib import specgrams_helper
  import numpy
  import tensorflow.compat.v1
label_desc: Use image node_id 1 for calling the SpecgramsHelperTest obj's underlying member method code with example usage: obj.setUp() without return types